Observer Pattern (옵저버 패턴)

가상 스테이션

다이어그램

IDisplay.cs

public interface IDisplay
{
    void Display();
}

IObserver.cs

public interface IObserver
{
    void Update();
}

ISubject.cs

public interface ISubject
{
    void RegisterObserver(IObserver observer);
    void RemoveObserver(IObserver observer);
    void NotifyObserver();
}

WeatherData.cs

public class WeatherData : ISubject
{
    private readonly List<IObserver> _observers = new List<IObserver>();

    public float Temperature { get; set; }
    public float Humidity { get; set; }
    public float Pressure { get; set; }

    public void MeasurementsChanged()
    {
        NotifyObserver();
    }

    public void RegisterObserver(IObserver observer)
    {
        _observers.Add(observer);
    }

    public void RemoveObserver(IObserver observer)
    {
        _observers.Remove(observer);
    }

    public void NotifyObserver()
    {
        _observers.ForEach(item => item.Update());
    }

    public void SetMeasurements(float temp, float humidity, float pressure)
    {
        Temperature = temp;
        Humidity = humidity;
        Pressure = pressure;
        MeasurementsChanged();
    }
}

CurrentConditionsDisplay.cs

public class CurrentConditionsDisplay : IObserver,IDisplay
{
    private float _temperature;
    private float _humidity;
    private readonly WeatherData _weatherData;

    public CurrentConditionsDisplay(WeatherData weatherData)
    {
        _weatherData = weatherData;
        _weatherData.RegisterObserver(this);
    }

    public void Display()
    {
        Console.WriteLine($"Current conditions : temperature : {_temperature}, humidity : {_humidity}%");
    }

    public void Update()
    {
        _temperature = _weatherData.Temperature;
        _humidity = _weatherData.Humidity;
        Display();
    }
}

나머지 코드는 git에…

git 주소 : Design Patterns with CS